The biphasic nature of renal calcification.

RENAL CALCIFICATION, INDUCED IN RATS BY AN INJECTION OF URANIUM, IS ACCOMPLISHED IN TWO STAGES: a primary accumulation of calcium in association with anions other than phosphate and a secondary conversion of this calcium complex into a precipitate of calcium phosphate. Except for the exclusion of chondroitin sulfate, the nature of the primary anions remains undefined. The accumulation of calcium in the kidney was converted into a precipitate of minimum solubility, and thus the evidence of its primary causation was obliterated. This may well hold true of calcification at other situations.